Operators of networks often provide numerous types of data, video and/or audio content to the premises of network users. Such content may include programming from broadcast television networks (e.g., ABC, CBS, NBC), from “cable” programming service providers (e.g., HBO, ESPN), programming from local television stations, and numerous other types of content. Numerous techniques have been used to deliver content data to users over coaxial cable, fiber optic cable and other types of physical media. In many cases, a physical medium connected to a user premises will continuously deliver each of multiple content-containing services that are available to the user. For example, one set of services may be carried in a first frequency band, a second set of services in a second frequency band, etc. A user wishing to view content from one of those services may utilize a device to tune to the appropriate frequency sub-band and isolate data packets in the frequency sub-band for the desired content.
In recent years, internet protocol (IP) television (IPTV) techniques have been developed to deliver some types of programming content in a unicast setting, such as a video-on-demand service. Using such techniques in a multicast environment presents additional challenges, however. In particular, business and/or regulatory restrictions may limit the users to whom, and/or the regions where, certain types of content can be provided. As one example, a “blackout” provision in network operator's contract with a sports franchise or programming service provider may prohibit delivering coverage of a particular sports event in certain areas. If the network operator uses IP multicast techniques to deliver that programming, a user in a blacked-out region obtaining the IP multicast group address for that coverage could potentially circumvent the blackout by seeking to join the multicast group. Known solutions to this problem (e.g., encrypting content, stopping content at a local router serving the user) have been less than satisfactory.